28157770 has 16 divisors (see below), whose sum is σ = 50826600. Its totient is φ = 11231424.

The previous prime is 28157741. The next prime is 28157771. The reversal of 28157770 is 7775182.

It can be written as a sum of positive squares in 4 ways, for example, as 26327161 + 1830609 = 5131^2 + 1353^2 .

It is a super-2 number, since 2×28157770² = 1585720022745800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28157771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45 + ... + 7504.

Almost surely, 2^28157770 is an apocalyptic number.

28157770 is a deficient number, since it is larger than the sum of its proper divisors (22668830).

28157770 is a wasteful number, since it uses less digits than its factorization.

28157770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7929.

The product of its (nonzero) digits is 27440, while the sum is 37.

The square root of 28157770 is about 5306.3895446904. The cubic root of 28157770 is about 304.2281657929.

It can be divided in two parts, 2815 and 7770, that added together give a triangular number (10585 = T₁₄₅).

The spelling of 28157770 in words is "twenty-eight million, one hundred fifty-seven thousand, seven hundred seventy".